I have a pair of AKG K 271's and have been generally really satisfied with them, they have served me well as closed cans on quite a few live/studio gigs as a sound engineer and they were also my headphones of choice for listening in either noisy or very quiet (so as to avoid disturbance) environments. For various reasons, I have not really used them in the last ~1 1/2 years (except for lending them to another audio engineer once), and when I plugged them in again last week, I was surprised to hear almost no bass at all.
As I don't really do audio work these days anymore, I don't easily have access to the necessary equipment to put numbers on that, but I'd say that everything below 200 Hz is noticeably lower, with a drop almost 10 dB at 100 Hz. I also had the chance to directly compare it against an AKG K 272, which is supposed to have the same drivers, and the difference is painfully obvious.
Now, I'm trying to figure out what is going on here. The first thing that came to my mind is a broken cable, but that's not the case, it works fine with a K 240. The next thing I checked was the ground wiring at the cable connector (as both channels are affected), but it seems to be fine as well, at least visually.
Any ideas what could be wrong here? I'm no stranger to using a scope and a soldering iron (which I'll try my luck with in the next few days), but I'm at a bit of a loss here. How likely is it that the drivers itself are "worn"? How would you go about tracking down the source of the issue further before just re-soldering all the ground connections, hoping to get lucky?
Edited by chephy - 2/21/13 at 3:02pm